Metastatic adenocarcinoma in a thyroid colloid nodule: a rare presentation of colon cancer.

Colorectal cancer can remain asymptomatic for years. Frequently symptoms develop insidiously and may often remain unnoticed for long periods, even in the presence of disseminated disease. We herein report an unusual case of a patient with carcinoma of the sigmoid colon and multiple liver metastases. The diagnosis was established only after the patient was operated on for a large colloid nodule, a single microscopic metastatic focus being noticed in the histologic sections. The differential diagnosis compared with the columnar type of papillary carcinoma is discussed.